Research On Internal Wind Environment Of An 800-meter-span Dome

With the rapid development of the large span building technologies, kilometer-span super domes which can cover large areas of a city began to come to people’s mind. When the dome span reaches kilometer scale, it’s a problem to create a comfortable interior wind environment, which should be considered in the designation. For a superlarge-span city dome, its internal environment under natural ventilation should not only meet the basic needs of ventilation and thermal comfort requirements, but also be focused on the natural environment of wind inside the dome, which may have caused wind environmental issues. However, studies on internal wind environment in superlarge-span domes remains to be further researched.In this dissertation, the internal wind environment of a planned 800-meter-span dome under natural ventilation is studied by FLUENT. Firstly, CFD simulation method and the evaluation criteria of comfort in the city dome are studied. Based on the above, the internal wind environment is analyzed under natural ventilation of coupling thermal pressure and wind pressure, and the recommendations are given about the vent setting forms. After extensive parametric analyses on vent parameters, the distribution features of temperature and flowing inside the large-span-dome are concluded. At last, the influences of external factors on the internal wind environment are discussed.The research is concluded as follows:1. The CFD simulation method of the internal wind environment considering both thermal pressure and wind pressure is proposed. The effectiveness of simulation of the natural ventilation(including wind pressure ventilation, thermal pressure ventilation and coupling wind pressure and thermal pressure ventilation) is verified. The method of parameter setting on the simulation of sunshine influence and coupling thermal pressure and wind pressure are proposed, laying the foundation to further research on the internal wind environment under natural ventilation.2. On the basis of summarising the research achievement on the comfort at home and abroad, combining the characteristics of the internal environment of super-largespan domes, the comfort evaluation criteria suitable for urban dome is estabilished, which considers the rate of ventilation, thermal comfort and wind speed.3. The influence of vent position, vent area, altitude difference between inlet and outlet on the interior wind environment is analyzed, regardless of the wind pressure. Discussing the quantitative relationship between ventilation and vent parameters through 125 examples, the recommended values about vent areas and altitude difference between inlet and outlet is concluded based on the requirement of thermal ventilation, ensuring the comfortable interior wind environment under thermal ventilation.4. According to 5 typical vent layout schemes most commonly used in large space buildings, the interior wind environment of the 800-meter-span dome under corresponding vent layout schemes are analysed, considering the influence of wind pressure. The vent layout scheme for the 800-meter-span dome is recommended. At last, the characteristics of distribution of temperature field and flowing field inside the largespan-dome are concluded by analyzing 27 examples.5. The influences of external factors such as wind speed, wind azimuth, sunshine radiation, and outdoor temperature on the interior wind environment are analyzed through 70 examples, revealing that southeast wind with the speed of 4m/s is the most favorable wind condition for the dome in Harbin during summer. The satisfaction rate of thermal comfort degree is in the range of 94% to 98% in all wind azimuths. The internal wind environment is the worst when the main inlet direction and wind direction have the gap of 90 degree to 120 degree.